The present invention relates to the art of removable covers for pressure devices and, more particularly, to an improved arrangement for releaseably clamping a removable cover on a pressure device.
It is of course well known to provide an opening into a pressure device with a removable cover to enable access to the interior of the device for a variety of purposes. Such a pressure device may be a tank, pipeline, autoclave, or other processing, storage or fluid delivering equipment wherein a high pressure, or vacuum, exists during use thereof. Such pressure devices generally require frequent access to the interior thereof and, accordingly, it becomes desirable to provide for such access to be easily, quickly and safely obtained.
In certain closure devices heretofore provided for an access opening to such a pressure device, the pressure device opening and the cover member for closing the latter are provided with radially projecting circumferential flanges which are facially and clampingly interengaged by a circumferentially extending clamping ring arrangement. When it is desired to gain access to the interior of the pressure device through the opening, the clamping components are displaced laterally outwardly of the flanges to release the cover for removal from the device and, when it is again desired to close the opening, the cover is repositioned thereacross and the clamping components are displaced laterally inwardly of the flanges to interengage the cover and pressure device. In connection with the lateral outward displacement of the clamping components to release the cover, it is of course necessary to first vent the interior of the pressure device in that the slightest pressure therein, either above or below atmospheric pressure, can result in sudden axially outward displacement of the cover member upon release of the clamping assembly. Such sudden displacement of the cover member is of course dangerous and undesirable, both from the standpoint of the safety of personnel and from the standpoint of potential damage to the component parts of the closure assembly. Accordingly, it becomes desirable to positively prevent the occurrence of such sudden displacement of the cover and the disadvantages attendant thereto.
Often, there are space limitations which restrict the extent to which the clamping ring components can project laterally outwardly of the opening into the pressure device. In any event such lateral projection of the clamping ring members can be hazardous to personnel whereby it is desirable to minimize the extent of projection. In clamping arrangements including a pair of semi-circular clamping members in which the lower ends of the clamping members are pivotally interconnected with the pressure vessel, the lateral outward displacement of the clamping ring members required to provide clearance for axial displacement of the cover member from the pressure device can result in excessive lateral outward projection of the clamping ring members. Moreover, the acutating mechanisms for displacing the clamping ring members have heretofore been relied upon to support the clamping ring members in their laterally outermost positions. As a result thereof, together with the extent of displacement required with respect to the clamping ring members, the actuating mechanisms and the mounting arrangements therefor have to be structurally massive to provide the necessary strength and structural integrity for the ring displacing and supporting functions. Furthermore, the actuating mechanisms have been relied upon to maintain the clamping ring members in axial alignment with the flanges of the cover member and pressure device and, when the clamping ring members are in the laterally outermost positions thereof, stability with respect to preventing axial displacement thereof and thus misalignment, is not adequately provided for by the actuating mechanism.